Cockatiels can be taught to talk. Although they tend to not be as talkative other species of parrots, cockatiels can learn to mimic words and phrases. A cockatiel's speaking voice is more muffled and unclear compared to that of larger parrots.
If a person wants a pet cockatiel that will talk more, a male is a better choice than a female. Vocalization is a natural male courtship behavior, so that influences their ability and interest in talking. However, as male cockatiels age, the hormones that are connected to this courtship behavior drop, so a previously chatty bird may become more quiet.